组蛋白修饰对喉癌细胞系中RASSF1A基因表达的影响

The effect of histone modification on RASSF1A gene expression in laryngeal carcinoma cell line

目的:探讨喉癌细胞中RASSF1A基因表达水平与基因组蛋白修饰的关系。方法:应用染色质免疫沉淀技术(ChIP)和实时定量逆转录聚合酶链反应(Realtime-PCR)分析喉癌Hep-2细胞系在以下药物:5-氮杂-2'-脱氧胞苷(5-Aza-2'-deoxyeytidine,5-Aza-dC,DNA甲基转移酶抑制剂,5-AZa-dC);曲古抑菌素A(TriChostatinA,TSA,组蛋白去乙酰化酶抑制剂)作用前后RASSF1A基因启动子区域组蛋白H3-K9甲基化、H3-K4甲基化、H3-K9乙酰化和RASSF1A基因表达情况。结果:TSA能轻度降低RASSF1A基因启动子区域组蛋白H3-K9甲基化水平、轻度提高H3-K4甲基化水平、明显提高H3-K9乙酰化水平。5-Aza-dC明显降低启动子区域H3-K9甲基化程度、明显提高H3-K4甲基化水平、提高H3-K9乙酰化水平,联合给予5-Aza-dC和TSA起协同增效作用。H3-K9甲基化水平降低、H3-K4甲基化和H3-K9乙酰化水平提高可使RASSF1A基因表达上调。结论:喉癌细胞中RASSF1A肿瘤抑制基因表达下调与其启动子区H3-K9甲基化、H3-K4甲基化和H3-K9乙酰化相关。甲基化抑制剂及乙酰化制剂均可使表达下调的基因表达上调。

Objective：To explore the correlation between RASSF1A gene expression and gene histone modification.Methods： ChIP and Realtime-PCR were used to detect H3-K9 methylation,H3-K4 methylation,and H3-K9 acetylation of RASSF1A gene promoter region and gene expression before and after treatment with drugs 5-Aza-2＇-deoxyeytidine（5-Aza-2＇-deoxyeytidine,5-Aza-dC,DNA methyltransferase inhibitor 5-AZa-dC） and TriChostatinA（TriChostatinA,TSA,histone deacetylase inhibitor）in laryngeal carcinoma Hep-2 cell line.Results： TSA was able to reduce H3-K9 methylation slightly,increase H3-K4 methylation slightly,and increase H3-K9 acetylation significantly of RASSF1A gene promoter region histone.5-Aza-dC was able to reduce H3-K9 methylation significantly,increase H3-K4 methylation significantly,increase H3-K9 acetylation.Synergistic effect was observed with combination of 5-Aza-dC and TSA.The reducing of H3-K9 methylation and increasing of H3-K4 methylation and H3-K9 acetylation were able to up-regulate gene expression.Conclusion： Down-regulation of RASSF1A tumor suppressor gene expression in laryngeal carcinoma cells is correlated with H3-K9 methylation,H3-K4 methylation and H3-K9 acetylation in its promoter region.Both methylation inhibitor and acetylating agent are able to up-regulate the down-regulated gene expression.